#box1 {
	width: 500px;
	height: 300px;
	border: 1px solid #ccc;
	display: flex;
	justify-content: center;
	align-items: center;
}

#box2 {
	width: 300px;
	height: 100px;
	border: 1px solid #ccc;
}

#box3{
	width: 1200px;
	overflow: auto;
	border: 1px solid #ccc;
	padding: 20px 0;
	display: flex;
	justify-content: space-around;
}

#box4 {
	width: 400px;
	height: 300px;
	background-color: #ccc;
}

#box5 {
	width: 760px;
	height: 300px;
	background-color: aliceblue;
}

/* 多列布局 */
#box6 {
	width: 1200px;
	overflow: auto;
	border: 1px solid #ccc;
	display: flex;
	justify-content: space-between;
}

#box7,#box8 {
	width: 220px;
	height: 300px;
	background-color: gray;
}

#box9 {
	width: 350px;
	height: 300px;
	background-color: gray;
}

#box10 {
	width: 300px;
	height: 300px;
	background-color: gray;
}

#nav {
	width: 100%;
	height: 50px;
}

#nav ul {
	width: 1200px;
	height: 50px;
	margin: 0 auto;
	list-style: none;
	display: flex;
	flex-wrap: nowrap;
}

#nav ul li {
	height: 50px;
	margin: 0 1px;
	flex-grow: 1;
}

#nav ul li a {
	display: block;
	height: 50px;
	line-height: 50px;
	font-size: 20px;
	background-color: blue;
	color: white;
	text-align: center;
}

.box {
	width: 200px;
	height: 100px;
	border: 1px solid #ccc;
}
.container {
	width: 100%;
	height: 400px;
	background-color: aqua;
	position: relative;
}
.static {
	position: static;
}
.relative {
	position: relative;
	left: 30px;
}
.fixed {
	position: fixed;
	right: 0;
	bottom: 0;
}
.absolute {
	width: 100%;
	height: 30px;
	line-height: 30px;
	background-color: rgba(0, 0, 0, 0.2);
	position: absolute;
	bottom: 0;
	left: 0;
}